The present invention relates generally to a motorized drive unit for operating a valve. Specifically, the present invention relates to a motorized drive unit, utilizing a small torque motor, for operating both gate and ball valves. Further, the present invention relates to a mounting device for coupling the drive unit to a valve such that the valve handle and the drive unit may translate along an axis defined by the valve stem without impairing the operation of the drive unit. In addition, the present invention relates to a first method for mounting the motorized drive unit to a gate valve and a second method for mounting the motorized drive unit to a ball valve.
Motorized drive units for operating valves are known in the prior art. One use for motorized drive units has been in automatic programmable water shutoff devices. Automatic programmable water shutoff devices are employed to shut off the flow of water through a plumbing pipe when a preset flow condition is detected in the pipe. Automatic programmable water shutoff devices typically include a motorized drive unit mounted to a valve, a computerized controller for presetting shutoff flow conditions, and a microphone for detecting fluid flow through a pipe. Automatic programmable water shutoff devices typically attach to the main water shutoff valves of residential buildings. There are generally two basic approaches for coupling the motorized drive unit to the valve. The first approach involves removing the handle of the valve and coupling the motor to the valve stem. The second approach involves attaching a gear to the valve stem and utilizing a chain for coupling the gear to the motor. Both of these automatic programmable water shutoff devices have had limited effectiveness for the reasons described below.
First, residential water shutoff valves are generally not manufactured to strict tolerances. Often the valve stem and handle exhibit some degree of motion, in excess of the intended rotation, during the operation of the valve. If the motor of the drive unit has been mounted to the water main, the movement of the valve stem and handle typically impairs the operation of the motor itself or causes the drive unit chain to bunch, bind, or fall off the gear sprockets. In either case, the automatic programmable water shutoff device is thereby disabled.
Second, the relatively small diameter of the typical valve stem requires the use of a high torque motor for automatic programmable water shutoff devices that attach directly to the valve stem. Typically, high torque motors are larger and more expensive than low torque motors. Therefore, using a high torque motor increases the cost of the device as well as increases the space required for installation.
Third, automatic programmable water shutoff devices that used a motor attached directly to the valve stem typically required the use of a valve stem connector to couple the motor to the valve stem. Each given valve stem connector was manufactured to operate for a given range of stem sizes. Additionally, the torque of the motor had to be matched to the particular size of the valve stem. However, as there is no standard stem size for residential water shutoff valves, there was not a standard size valve stem connector and motor. Thus, the consumer had to know the stem size and valve torque prior to purchasing an automatic programmable water shutoff device. The typical homeowner would be more inclined to purchase a product that was adaptable to a greater range of valve stem sizes and torques.
Fourth, prior automatic programmable water shutoff devices could not operate ball valves. A ball valves handle acts as a stop to prevent the valve from over-rotating in either the opening or closing direction. With a ball valve handle attached to a ball valve stem, there is no room for the valve stem connector of prior automatic programmable water shutoff devices to couple to the valve stem. Because ball valves, in addition to gate valves, are commonly used in residential applications, prior automatic programmable water shutoff devices were not adapted for use in a significant number of residential applications.
Fifth, prior automatic programmable water shutoff devices were not easily installed by the typical homeowner. Providing an automatic programmable water shutoff device that is easier for the typical homeowner to install would increase the market potential of such devices.
Accordingly, it would be desirable to provide a motorized drive unit for use in a automatic programmable water shutoff device that (1) is not impaired by the translation of the valve handle and drive unit in the direction of the valve stem, (2) uses a low torque motor, (3) is adaptable to typical valve stem sizes and torques, (4) works with both gate and ball valves, and (5) can easily be installed by the typical homeowner.
It is one of the principal objectives of the present invention to provide a motorized drive unit that can be installed by the typical homeowner.
It is another objective of the present invention to provide a motorized drive unit for mounting to a gate valve.
It is yet another objective of the present invention to provide a motorized drive unit for mounting to a ball valve.
It is still another objective of the present invention to provide a gear that can be mounted to a valve handle such that a low torque motor may be implemented for operating the valve.
It is a further objective of the present invention to provide a device for coupling a drive unit to the range of valve stem sizes typically used in residential plumbing applications.
It is another objective of the present invention to provide a device for coupling a drive unit to a valve such that translation of the valve handle and drive unit in the direction of the valve stem axis does not impair the operation of the drive unit.